July 30, 2020 7:03:40 am
The Russian candidate vaccine for novel Coronavirus is back in the news again. According to report by Bloomberg, Russia was planning to ‘register’ its novel Coronavirus vaccine by August 10-12.
The vaccine, developed by Moscow’s Gamaleya Research Institute of Epidemiology and Microbiology, was likely to be approved for public use “within three to seven days of registration by regulators”, said the report.
This is the same vaccine that was, earlier this month, reported to have successfully completed human trials. Actually, at that time, in the second week of July, this candidate vaccine had only completed phase-I human trials. Its phase-II trials began on July 13, according to a report in TASS news agency at that time.
A vaccine is usually not approved for public use till it completes three phases of human trials, each of which, in normal circumstances, can run for several months.
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It appears, however, that Russia was planning to finish phase-II trials early, and approve the vaccine for use, without phase-III trials.
The Bloomberg report said the Gamaleya vaccine was likely to get “conditional registration” in August, meaning it would be approved for use, even as phase-III trials are carried out. The production of the vaccine was expected to begin in September, the report said. Till the clinical trials are completed, the vaccine is likely to be administered only to health professionals, it said.
Phase-I trials assess the safety of the vaccine in human beings. It usually is carried out on small number of people, in the range of a few dozen, and runs from a few weeks to a few months. In phase-II, the vaccine’s ability to trigger immune response against the disease is assessed. In this phase, the vaccine is tested on a few hundred volunteers.
The third and final phase is usually conducted on several thousand volunteers. One group of volunteers are injected with the vaccine while another group is given a dummy vaccine. The volunteers go about their normal lives, and assessed a few weeks later to see whether the group that had been injected with the vaccine had shown any particular resistance to the infection. This phase can take several months.
Scientists and health experts warn against releasing a vaccine in haste, insisting that all safety and efficacy tests must be carried out before it is approved for use.
Serum’s plans to start testing Oxford vaccine on Indians by August halted
The plans of Pune-based Serum Institute of India to start testing the Oxford vaccine on Indian participants by August has hit a hurdle. An expert committee studying the firm’s proposal for trials has asked it to make revisions. This means that the committee’s approval for the trials has been deferred and it is unclear how long Serum would have to wait before it can begin testing the vaccine on Indian participants.
What is this vaccine?
Being developed by the Oxford University and AstraZeneca, this candidate vaccine is one of the front-runners in the global race to develop a vaccine against novel Coronavirus. Named ChAdOx1, this vaccine tries to use a weakened chimpanzee virus (adenovirus) to carry instructions to the cells in human bodies to recreate the spiky surface of the Covid-19 virus. Once this is done, the body’s immune system is expected to recognise these foreign particles as a threat, and create antibodies so that attempts by the real Coronavirus to infect are thwarted.
This vaccine candidate is currently undergoing late stage human trials in the UK, Brazil and South Africa. Serum has an agreement with AstraZeneca to manufacture it for low and middle income countries.
What is this expert committee, and why has it held back its approval?
India’s top drug regulatory body, the Central Drugs Standard Control Organisation (CDSCO), makes decisions related to clinical trials based on recommendations of subject expert committees (SECs). Serum’s proposal was being studied by one such SEC.
In its application, Serum had proposed phase-II and phase-III trials on about 1,600 participants. The SEC has sought a demarcation between the two phases. While it is not yet clear whether the Pune-based firm was considering testing sites only in Pune and Mumbai, as it had indicated earlier, the SEC is learnt to have insisted that the test sites should be spread out all over the country.
The SEC is learnt to have recommended about eight amendments to Serum’s application. This includes suggestions related to methods adopted to assess the ability of the candidate vaccine to invoke an immune response, and the firm’s calculations to determine the number of volunteers the tests would be carried out on.
What happens now
Serum would have to make changes to its proposal and come back to the committee. If the SEC is satisfied it can then recommend the trials. Only after the SEC makes its recommendation, can the Drug Controller General of India, who heads CDSCO, would grant approval for conducting the trials in India.
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Moderna vaccine induced “robust immune response” on animals, says study
Moderna Therapeutics, a US biotech company considered one of the front-runners to produce a vaccine against novel Coronavirus, has published data from pre-clinical trials of its candidate vaccine in a peer-reviewed journal. The publication in New England Journal of Medicine says the candidate vaccine had elicited “robust immune response and protection” against the virus in the subjects.
Pre-clinical trials are conducted on animals. If successful, the vaccine is then tested on humans in three phases.
Moderna’s candidate vaccine, named mRNA-1273 for the time being, has just entered the third and final phase of human trials. It has published findings of phase-I human trials as well, but these were based on preliminary data. The subjects on whom the vaccine is tried are followed up for several weeks to assess their condition.
Moderna’s candidate was the first to get approval for pre-clinical trials, way back in February itself. The animals were given two doses of the candidate vaccine during the trial.
“After two vaccinations, the immune response observed in this non-human primate study was consistent with the recent Phase 1 human study of mRNA-1273, also published in The New England Journal of Medicine,” the company said in a. statement.
“This important preclinical study shows that mRNA-1273 protected against a high dose SARS-CoV-2 infection in non-human primates and prevented pulmonary disease in all animals, further supporting the clinical advancement of mRNA-1273,” the company said.
The interim analysis of phase-I human trials had found that the vaccine had triggered immune response in all the participants.
The Story So Far
- 25 candidate vaccines in human trials
- Five in Stage-III trials
- 139 candidates in pre-clinical trial stage
- Two Indian candidates in Stage-I trials
Also in Explained | Why India will remain a central player in the development of vaccines
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